You attempt to interrupt a creature in the process of Casting a Spell
. If the creature is Casting a Spell
of 3rd level or lower, its spell fails and has no effect. If it is Casting a Spell
of 4th level or higher, make an ability check using your Spellcasting Ability
. The DC equals 10 + the spell's level. On a success, the creature's spell fails and has no effect.
At Higher Levels: When you cast this spell using a spell slot of 4th level or higher, the interrupted spell has no effect if its level is less than or equal to the level of the spell slot you used.